Part 4 :Examining Volcanos and Earthquakes: Is there a correlation between the two?
Part 4 By Natalie Marcom
Adding onto the discussion of how earthquakes affect tsunamis, we will also discuss how earthquakes may affect volcanic eruptions. There are approximetely 1.5k active volcanos on earth. However, I will focus on connecting earthquakes and volcanic eruptions to stay within the scope of the class, as I am not a geophysicist.
I used data from NOAA, a website from Oregonstate.edu with the list of volcanos with their latitude and longitude, volcano and plate boundary shapefiles from ArcMap (Esri), as well as data from volcanodiscovery.org to find data concerning recent earthquakes near volcanos.
import requests
from lxml import html
from mpl_toolkits.basemap import Basemap
import numpy as np
import pandas as pd
import matplotlib.pyplot as plt
Let's plot all 1500 volcanos on a map to see where most of them are located. Due to the difficulty to acquire a reasonable dataset of volcanos, besides a shapefile from Arcmap, we will scrape from a website that indicates the Latitude and longiude of all the volcanos to make plotting easy. We will also plot the volcanos on a basemap by the size of the volcano, via it's elevation height in meters.
page = requests.get('http://volcano.oregonstate.edu/oldroot/volcanoes/alpha.html')
tree = html.fromstring(page.content)
tables = tree.xpath('//table')
volcano_data = []
for volc in range(4, len(tables)):
df = pd.read_html(html.tostring(tables[volc]), header=0)[0]
volcano_data.append(df)
df_volc = pd.concat(volcano_data, ignore_index=True)
Let's look at a small snippet of the volcano dataset that was scraped. We will take note of the main observations of this dataset.
df_volc.head(10)
Where are the volcanos located? Are they near tetonic plates?
import pandas as pd
from mpl_toolkits.basemap import Basemap
import matplotlib.pyplot as plt1
import matplotlib as mpl
import shapefile
from mpl_toolkits.basemap import Basemap
import geopandas as gp
import os as osf
osf.chdir('C:\Users\jenat\\Documents\\ringoffire\\new')
volc = gp.GeoDataFrame.from_file('volcs.shp')
plt1.figure(figsize = (20, 12))
y = volc.LATX
x = volc.LONGX
map1 = Basemap()
map1.readshapefile('plate', 'plate')
map1.drawmapboundary(fill_color = 'lightskyblue')
map1.fillcontinents(color = 'lavender',lake_color = 'aqua')
map1.drawcountries()
map1.drawcoastlines()
volc_info = map1.readshapefile('volc1', 'volcs')
x1,y1 = map1(x,y)
map1.scatter(x1,y1,c = 'red',marker = "o",alpha = 1.0)
plt1.title("Map of Volcanos and Plate Boundaries", fontsize = 25)
plt1.show()
Using two shape files (one for plate bounaries, the other of the world's volcanos), we see that majority of the volcanos are very close to plate boundaries, that or they are along the tetonic plate boundaries.
However, besides plotting the volcanos on a map, let us take it a step further and plot volcanos as well as data that indicates whether one of these volcanos, had an eruption that was associated with an earthquake. We will use two datasets to answer this question. The second dataset with the earthquake information mainly looks at volcano eruptions from 1790 to the present. I have decided to look at world volcanos for that data and not focus on a particular region of the world.
How many of the volcanos have had eruptions that were associated with earthquakes?
</u>
import os
import pandas as pd
from mpl_toolkits.basemap import Basemap
import numpy as np
import pandas as pd
import matplotlib.pyplot as plt
os.chdir('C:\Users\jenat\Documents')
#second dataset
data = pd.read_csv("new_world_data_results_up1.csv")
data
def plot_map2(lons, lats, elevations, llcrnrlat = -80, urcrnrlat = 90, llcrnrlon = -180, urcrnrlon = 180,resolution = 'i', projection='mill', lat_0 = 39.5, lon_0 = 1,min_marker_size=5):
bins = np.linspace(0, elevations.max(), 10)
marker_sizes = np.digitize(elevations, bins) + min_marker_size
m2 = Basemap(projection=projection, llcrnrlat=llcrnrlat, urcrnrlat=urcrnrlat, llcrnrlon=llcrnrlon, urcrnrlon=urcrnrlon, resolution=resolution)
m2.drawcountries()
m2.drawmapboundary(fill_color='lightskyblue')
m2.fillcontinents(color = '#ddaa66',lake_color='aqua')
m2.drawcoastlines()
for lon, lat, m2size in zip(lons, lats, marker_sizes):
x, y = m2(lon, lat)
m2.plot(x, y, 'bs', markersize=m2size, alpha=.7, zorder=4)
return m2
def plot_map1(lons, lats, elevations, llcrnrlat=-80, urcrnrlat=90, llcrnrlon=-180, urcrnrlon=180,resolution='i', projection='mill', lat_0 = 39.5, lon_0 = 1,min_marker_size=2):
bins = np.linspace(0, elevations.max(), 10)
marker_sizes = np.digitize(elevations, bins) + min_marker_size
m = Basemap(projection=projection, llcrnrlat=llcrnrlat, urcrnrlat=urcrnrlat, llcrnrlon=llcrnrlon, urcrnrlon=urcrnrlon, resolution=resolution)
m.drawcountries()
m.drawmapboundary(fill_color='lightskyblue')
m.fillcontinents(color = '#ddaa66',lake_color='aqua')
m.drawcoastlines()
for lon, lat, msize in zip(lons, lats, marker_sizes):
x, y = m(lon, lat)
m.plot(x, y, '^r', markersize=msize, alpha=.7, zorder=4)
return m
plt.figure(figsize=(60, 30))
m2 = plot_map2(data['Longitude'], data['Latitude'], data['Elevation'], min_marker_size=35)
m = plot_map1(df_volc['Longitude'], df_volc['Latitude'], df_volc['Elevation (m)'], min_marker_size=10)
plt.title('Volcano Eruptions with Associated Earthquakes', color='#000000', fontsize=50)
plt.show()
In the original NOAA dataset, there are 797 volcanic eruption observations, and 55 of them are eruptions associated with earthquakes. Taking this into account from this dataset (Volcanic eruptions from 1790-2016), 6.9% of the volcanic eruptions from the NOAA dataset, had an association with an earthquake.
The red triangles indicate the volcanos, and the blue squares indicate the volcanos who had an association with an earthquake prior to its eruption. Out of 1500 volcanos, there were about 55 volcanic eruptions that had this association. Many have these occurred in the 20th century. We also see that the majority of these earthquake and volcano association have happened along the ring of fire, which stretches along the Eastern edge of Asia, down to New Zealand, as well as from Alaska down to South America.
Closer Examination of Volcano Eruptions with Associated Earthquakes
</u></center>
Let's examine the different types of volcanos as well as the top 10 countries that had the most volcanic eruptions with associated earthquakes. Is there a particular region that had the most volcano eruptions?
import matplotlib.pyplot as plt; plt.rcdefaults()
import numpy as np
import matplotlib.pyplot as plt
Is there a type of Volcano that is more frequent with eruptions?
objects = ('Stratovolcano', 'Shield Volcano', 'Complex Volcano', 'Pyroclastic shield', 'Tuff cone', 'Fissure vent','Submarine volcano')
y_pos = np.arange(len(objects))
performance = [38,7,6,1,1,1,1]
plt.barh(y_pos, performance, align='center', alpha=0.5)
plt.yticks(y_pos, objects)
plt.xlabel('Amount')
plt.title('Variation of Volcano Types with Associated Earthquakes')
plt.show()
We see that stratovolcanos (for instance Mount St.Helens, is a stratovolcano) had the overall highest frequency of volcanic eruptions, and by a large proportion.
Which country has had volcanic eruptions the most?
data['Country'].value_counts()[:10].plot(kind = 'barh', title = 'Top 10 Countries with Volcanic Eruptions with Associated Earthquakes')
plt.show()
We see that the United States and Japan have an equal amount of volcanic eruptions that had associations with earthquakes.
Due to the lack of magnitude observation, from the NOAA data (which gave an option of volcanic eruptions with association of earthquakes), a goal is to have a better observation of more detailed variables to help establish a correlatiopn between earthquakes and volcanic eruptions. However, because this is a topic that scientists are still debating, and many do not see an exact correlation between the two, we will take a different approach that may lead us to answers that we are looking for, which is establishing a correlation between earthquakes and volcanos.
Using data concerning earthquakes occurring close to volcanos
Examining link between Earthquakes and Volcanic eruptions
As stated before, scientists still are debating whether earthquakes and volcanic eruptions are connected or not, and there is a lack of information available that proved that the two are substantially linked to one or the other. However, I have found enough data indicating that earthquakes do occur near volcanos, which can suggest that it is possible for earthquakes and volcanos to be somewhat linked.
Is it possible for earthquakes and volcanos to come into close contact with one another?
import os
os.chdir('C:\Users\jenat\\Documents\\ringoffire')
import pandas as pd
import numpy as np
from mpl_toolkits.basemap import Basemap
import matplotlib.pyplot as plt
import matplotlib as mpl
os.chdir('C:\Users\jenat\Documents\\ringoffire')
eqdata = pd.read_csv('earthquakesdata.csv')#dataset
eqdata1 = eqdata.convert_objects(convert_numeric=True)
Feb and March 2017 Earthquakes near Volcano data:
</center>
eqdata1
These are two small datasets consisting of earthquakes that have happened near volcanos since Feb 1-March 18th. As we can see from these datasets, particularly the distance (km) from the volcano itself, we see that it is very likely that earthquakes and volcanos can come into close contact with another, thus the possibiltiy of volcanic eruptions and earthquakes occurring is a possibility, as it is proven in the first dataset. The question remains, how frequenly does it occur, and what causes it (two questions for Geologists!)
latlong = pd.read_csv('latlong.csv')
eqdata = pd.read_csv('earthquakesdata.csv')
#earth.Latitude
#earth.Longitude
def earth_near(lons, lats, magnitude, min_marker_size=2):
bins = np.linspace(0, magnitude.max(), 10)
marker_sizes = np.digitize(magnitude, bins) + min_marker_size
m = Basemap()
m.readshapefile('C:\Users\jenat\\Documents\\ringoffire\\new\\plate', 'plate')
m.bluemarble(alpha=0.42)
for lon, lat, msize in zip(lons, lats, marker_sizes):
x, y = m(lon, lat)
m.plot(x, y, '*', c='#fff8dc',markersize=msize, alpha=1.0, zorder=10)
return m
| Meaning | |
| * | Earthquake |
| o | Volcano |
| Line | Plate boundary |
plt.figure(figsize=(15, 12))
map1.scatter(x1,y1,c='red',marker="o",alpha=0.7)
m = earth_near(eqdata1['Longitude'], eqdata1['Latitude'], eqdata1['Mag'], min_marker_size=2)
plt.title('Earthquakes near Volcanos Since Feb 1', color='#000000', fontsize=40)
plt.show()
We see that they are quite close to tetonic plates. The white stars are the earthquakes, and the red circles are the volcanos. As we see, the earthquakes are all quite close to the volcanos. In addition, the size of the stars is based upon the magnitude of the earthquake.
Where are these earthquakes happening the most?
import matplotlib.pyplot as plt; plt.rcdefaults()
import numpy as np
import matplotlib.pyplot as plt
eqdata1['Location'].value_counts()[:10].plot(kind = 'barh', title = 'Top 10 Locations with Earthquakes near Volcanos since Feb 1')
plt.show()
For Top 3 (out of 10) : We see that New Zealand has had the most earthquakes, followed by the big island of Hawai'i, then Russia. We also see that Central California, southern California, Northern California (which should include the Geysers) also have a lot of activity as well.
Is there a specific magnitude that is happening more frequently?
plt.figure()
plt.hist(eqdata1['Mag'].dropna(), bins = 20)
plt.xlabel('Magnitude')
plt.ylabel('Amount')
plt.title("Variation and Amount of Earthquake Magnitudes Since Feb 1")
plt.show()
Most of the earthquakes magnitudes are quite small, as in 2.5 or below.
Is there a correlation between the depth of the earthquake and the magnitude of the earthquake?
import matplotlib.pyplot
import pylab
import os
os.chdir('C:\Users\jenat\\Documents\\ringoffire')
import pandas as pd
import numpy as np
import matplotlib.pyplot as plt
import matplotlib as mpl
tes3 = pd.read_csv('earthquakesdata.csv',usecols = [1,2])#dataset
data1 = tes3.convert_objects(convert_numeric=True)
data1 = data1.rename(columns={' Depth': 'Depth'})
matplotlib.pyplot.scatter(data1.Mag,data1.Depth)
matplotlib.pyplot.title('Scatter Plot of Magnitudes and Depths of Earthquakes')
matplotlib.pyplot.xlabel("Magnitude")
matplotlib.pyplot.ylabel("Depth (M)")
matplotlib.pyplot.show()
As we can see, there is not a strong correlation between Magnitudes of earthquakes and the depths of the earthquakes. Most of the earthquakes from smaller magnitudes to the larger ones are typically within the same range of depth, which indicates that magnitude an depth are likely not correlated.
Let's use a Spearman, non-parametric correlation test between Magnitude and Depth
import os
os.chdir('C:\Users\jenat\\Documents\\ringoffire')
import pandas as pd
data1.corr()
data1.corr(method='spearman', min_periods=1)
The matrix correlation, using the spearman test concerning the two columns magnitude and Depth, indicates too that there is not a strong correlation between Magnitude and Depth.
CONCLUSION
There is not enough scientific evidence, or data to link earthquakes and volcano eruptions as being statistically significant to one another. More specifically, if an Earthquake can cause a volcanic eruption. While scientists are still debating the connection between the two, there is evidence that earthquakes occur (and rather frequently) near volcanos. With that information given, this brings the possibility that it is possible for earthquakes and volcanos to correlate with one another.
Another aspect worth looking into, is determing which earthquake is an aftershock and which earthquake is not.